Rail car unloading pits are underground structures located below railroad tracks which support the railroad tracks and receive aggregate, particulate, or other material unloaded from rail cars. Rail car unloading pits typically consist of a floor and vertical walls which form one or more compartments. A conveying system, usually a series of belt conveyers placed in end-to-end fashion, is placed inside each compartment. A rail car containing a desired material is transported along the railroad tracks and is positioned to longitudinally straddle the unloading pit. Doors on the bottom of the rail car are opened and the material inside the rail car is discharged under the influence of gravity into the unloading pit. The discharged material is transferred by the conveying system from the pit to a remote location. As described below, prior unloading pits have been: (i) expensive and time consuming to install, (ii) non-reusable, and (iii) environmentally disagreeable.
Prior rail car unloading pits have been formed by excavating a site and pouring concrete in the excavation to a desired unloading pit shape, i.e., they are cast-in-place. Many cast-in-place unloading pits take three-to-four weeks and a significant number of man-hours to install due to their size, amount of concrete required, and concrete setting requirements.
In addition, after a cast-in-place unloading pit is no longer required at a site, its useful life is over and the pit is backfilled with dirt. However, backfilling a cast-in-place unloading pit is detrimental to the environment because all the concrete permanently remains underneath the ground surface. Even if one would attempt to remove a cast-in-place unloading pit from the excavation, it would be extremely costly and would still likely leave concrete remains underneath the ground surface, as the unloading pit would have to be forcibly broken into pieces and carried away.
There is a need, therefore, for an unloading pit which is inexpensive and time efficient to install, reusable, and environmentally friendly.